In general, a building such as a house is constructed at a building site. For instance, in the case of a wooden house, a framework is built on a concrete foundation at a building site using construction materials such as a beam and a pillar, and subsequently, housing equipment (equipment devices) such as water-related equipment and electrical equipment is installed.
Installation of the housing equipment at a building site may cause a variation in the quality and an increase in the cost. Thus, a technique in related art is known in which an equipment unit including a bathroom (modular bath) and a toilet is produced in a factory in advance, the equipment unit is transported to a building site, and the entrance, rooms and others are constructed on the site by a traditional construction method (PTL 1).